The present invention relates to a sound volume setting device for automatically adjusting a volume of a calling sound and a receiving speech sound of a portable telephone which can communicate through a public base station (cell station) or a base station of a home telephone. Examples of telephones to which the present invention can be applied are PHS (Personal Handy-phone System) terminals, cellular cordless telephones, and so on.
Conventionally, a PHS portable telephone is capable of communicating with a remote person through the nearest public base station outdoors, and through a home telephone as a home base station indoors. Generally, a PHS portable telephone automatically informs a system at all times, through a control channel, of the service area where the PHS telephone is by using data such as ID. In some cases, PHS telephones give information to each other.
Since a user carries a PHS porable telephone when the user uses it outdoors, the user usually sets its calling sound small, while, since the user often separates the telephone from the user's body when the user uses it indoors, the user sets the calling sound large. In addition, since a large noise often comes from surroundings (back noise) outdoors, the user generally sets the volume of its receiving speech sound large, and since it is often calm indoors, the user generally sets the volume of the receiving speech sound small.
In addition, as a conventional technique to adjust the volume of a receiving speech sound automatically, there is a method where the sound volume of surrounding noises is detected, and the volume of a receiving speech sound is adjusted automatically in accordance with the detection signal.
In addition, as for the adjustment of the volume of a calling sound, there is a method of increasing the sound volume as time passes, that is, as the number of times of a calling sound increases.
However, as mentioned above, it is very troublesome to set the volume of a receiving speech sound and the volume of a calling sound manually on all such occasions outdoors and indoors. In addition, there has been a problem that the method where the sound volume of surrounding noises is detected requires a large device and a high cost, and a method of increasing the volume of a calling sound as time passes causes a trouble such as a nuisance to others when there is a call in the crowd.